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Anticoagulant (parenteral)

Unfractionated Heparin (UFH)

Brand names: Heparin Sodium

Unfractionated heparin (UFH) is a parenteral anticoagulant, given intravenously or subcutaneously, used for treatment and prevention of venous thromboembolism, in acute coronary syndromes, and during procedures such as cardiopulmonary bypass, particularly where rapid, titratable and reversible anticoagulation is needed.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It binds antithrombin and greatly accelerates its inactivation of thrombin (factor IIa) and factor Xa, inhibiting fibrin formation; its effect is short-lived and reversible with protamine.

Prescribing in practice

  • Heparin-induced thrombocytopenia is a serious immune-mediated complication, so monitor the platelet count and stop heparin if it occurs.
  • Bleeding is the principal risk and the therapeutic intravenous infusion requires APTT-guided dose adjustment; protamine sulphate is the specific antidote.
  • Caution in renal and hepatic impairment, and with prolonged use hyperkalaemia and osteoporosis can occur.

Monitoring

Monitor the APTT (or anti-Xa) to guide therapeutic dosing and the platelet count for heparin-induced thrombocytopenia, with potassium on prolonged use.

Counselling the patient

  • Explain that the dose is adjusted by regular blood tests during treatment.
  • Report any unusual bruising, bleeding, or new limb swelling or pain.
  • Mention any previous reaction to heparin before treatment.

Evidence & guidelines

Unfractionated heparin with APTT monitoring and platelet surveillance for heparin-induced thrombocytopenia is established UK anticoagulation practice.

Reference: BCSH Guidelines; NICE NG158; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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